超声辐照对大鼠颈总动脉损伤后细胞凋亡的影响

Ultrasound Induced Cell Apoptosis Following Carotid Artery Injury in Rats

目的 观察不同频率 ,不同声强的超声辐照对大鼠颈总动脉球囊过扩张后平滑肌细胞凋亡的影响 ,为超声防止再狭窄筛选适宜的治疗参数。方法 3 5只雄性Wistar大鼠 ,体重 ( 3 5 0± 5 0 )g ,随机分为 7组 ,对照组用 2F球囊导管对大鼠颈总动脉进行过扩张 ;治疗组为球囊扩张 +超声辐照 ,在球囊扩张后分别用频率为 70 5kHz ,2 .17MHz ,5 .48MHz ,强度为 1W cm2 ,2W cm2 (共 6组 )的连续型超声波对损伤血管局部进行 3min照射。喂养 2周后取材 ,TUNEL标记法检测凋亡细胞百分率的改变 ,以观察超声辐照对血管平滑肌细胞凋亡的影响。结果 球囊损伤 2周后治疗组TUNEL阳性细胞率分别有不同程度的升高 ,与对照组比较 70 5kHz ,1W cm2 升高明显 [( 3 0 .2± 3 .8) %vs( 18.6± 2 .4) % ,P <0 .0 5 ) ] ,有显著差异 ,而其它 5组的TUNEL阳性细胞率有不同程度的升高 ,但与对照组比较 ,经统计学分析无差异显著(P >0 .0 5 )。结论 一定剂量的超声辐照能诱导大鼠颈总动脉损伤后血管平滑肌细胞凋亡。在本实验设置的参数中 ,70 5kHz、1W cm2 超声辐照能增加平滑肌细胞凋亡 。

Objective Ultrasound exposures (USE) at different frequency and intensity were investigated on the apoptosis of vascular smooth muscle cells (VSMC) at rat carotid artery after balloonplasty. Optimal ultrasound therapeutic parameters were found to prevent restenosis.Methods Thirty-five male Wistar rats(350±50 g) were randomly divided into seven groups: controlled group(only balloon dilation); built animal models after the carotid artery of rats was denudated by 2 Forgarty catheter; USE therapeutic group:ultrasound device made of mono-source of piezoelectric ceramics operating at 705 kHz, 2.17 MHz,5.48 MHz frequencies and 1 W/cm2, 2 W/cm2 intensities after balloon dilation. USE was applied locally to the injured blood vessels in the treatment group for 3 minutes. The target arteries were autopsied two weeks after the procedure. Apoptosis was studied respectively by TUNEL marking method. The ratio of apoptosis was also calculated to observe changes.Results TUNEL%: The ratio of positive cells marked by TUNEL in the USE group was higher than the controlled group after two weeks. The ultrasound group of 705 kHz, 1W/cm2 had statistical significance over the controlled (30.2±3.8% vs 18.6±2.4%, P<0.05), but other groups had no statistical significance (P>0.05).Conclusion USE at certain frequency and intensity resulted in a significant increase in apoptosis of VSMC following carotid artery injury on rats. In this experiment, USE at 705 kHz, 1 W/cm2 had a significant effect on increasing apoptosis of VSMC, it could potentially prevent the restenosis formation of blood vessel after balloonplasty.